Like others, I intend to use this app for stolen Mac recovery. It would be much more valuable for that purpose with whatever geo location info is possible to include with each snap (particularly WiFi ID and IPs), preferably in the EXIF data. This can be raw data that isn't converted to human readable location until necessary.
I suggest there also be a feature to automatically save only the last X number of snaps on the FTP server (or DAV, why not Dropbox and MobileMe) so that if the owner leaves this app on, the server isn't filled with useless snaps.
If the Mac is stolen, the snaps can be saved from the directory on the server before they are over-written by the newer snaps, allowing location data and snaps to help track down the perps and recover the Mac, and probably other items stolen.
My web dev apps are able to poll the server for file versions so that is why I think FTP/DAV can also be used to delete the oldest snaps on the server. I suggest the number of snaps saved on the server should be optional, as well as the snap interval. I would leave at least the last 200-300 on the server.